526 BRITISH PALZEOZOIC FOSSILS. (GasTERopopa. 
the upper or posterior one is much more strongly marked than the other, and interrupts the outline from the 
more abrupt convexity of the part of the whorl between it and the suture ; the band is a little above the middle 
of the body-whorl, and a little above the suture on the spiral whorls, where its lower bounding sulcus often 
becomes obscure, and its upper sulcus nearly equals the sutures in depth, and from being but very little below 
the middle, gives the appearance of twice the actual number of whorls in the spire ; base convex, with a very 
large callosity, filling the place of the umbilicus, divided by a medial spiral sulcus ; mouth broad-ovate, slightly 
longer than wide. Surface smooth. Diameter of average specimen one inch three lines, proportional height 
from base %, height of last whorl =, proportional height of penultimate whorl ;;;, width of callus ,¢,, width of 
mouth ;°. 
I do not know why M. de Koninck describes this species with eight whorls to the spire, while his figures 
agree with all our specimens in having only four to five, unless he may perhaps have counted by accident the 
strong upper sulcus of the band as one of the sutures. The species is very easily recognised by its He/ia-like 
form, obtuse convex band, and large callosity on the base. 
Position and Locality.—Not very uncommon in the carboniferous limestone of Arnside, Kendal. 
PLEUROTOMARIA CIRRIFORMIS (Sow. Sp.) 
Ref. and Syn. = Helix cirriformis Sow. Min. Con. t. 171. f. 2.=Pleurotomaria vittata Phill. Geol. York. t. 15. 
f. 24. = Pleurotomaria cirriformis (Sow.) de Kon. Supp. Anim. Foss. Bel. t. 58. f. 8. 
Desc.—Acutely conic, apical angle 80°; spire of six whorls, sloping and gently convex above; sutures 
simple, impressed; base of last whorl sloping, gently convex; band very broad, flat, only slightly projecting 
from the surface, its upper edge forming the most prominent part of the spiral whorls, the lower edge being 
concealed by the suture, on the body-whorl it is placed a little above the middle, the lower edge coinciding with 
the most prominent part of the outline; mouth slightly longer than wide, obtusely trapezoidal; umbilicus 
distinct, deep, rounded, narrow; surface marked with rather coarse, irregular lines of growth extending with 
slight obliquity towards the band arched near the sutures, crossed under the lens by extremely minute spiral 
strize, scarcely visible to the naked eye; band crossed by very faint minute arched striz. Length one inch one 
line, proportional height of mouth *, height of penultimate whorl =, diameter at base ;;,, width of mouth ;%, 
diameter of umbilicus ,7,, width of band on last whorl ;,. 
The great width and flatness of the band are the most remarkable features of this species, as well as 
the partial concealment of this latter by the edge of the sutures. The extreme minuteness of the spiral striz, 
and the absence of the two or three equidistant, strong, spiral grooves on the base, separate it from the 
P. tornatilis (Phill.) 
Position and Locality.—Rare in the carboniferous shale of Craige near Kilmarnock, 
PLEUROTOMARIA CoNICA (Phill.) 
Ref. and Syn.= Phill. Geol. York. Vol. II. t. 15. f. 22.;%+ P. decussata M°Coy, Synop. Carb. Foss. Irel. 
tee te diss: 
Dese.—Acutely conical; apical angle varying from 62° to 72°; spire composed of about seven gradually 
increasing, flattened whorls, slightly tumid towards their lower edge, where they have a very narrow band 
bounded by two strong thread-like keels, a little less broad than the band, and so much depressed as to form a 
deep sulcus between them; the pair of keels are about the width of the band above the suture, the intervening 
space being so depressed as to resemble a second sinal sulcus, and sometimes a third sulcus appears over the 
upper keel; body-whorl with the periphery obtusely angulated, and bearing two or three narrow keels, divided 
by deep sulci, one of which contains the slit of the mouth; umbilicus small, rounded, deep in the casts, 
nearly closed when the shell is perfect. Surface of the whorls above the band sculptured with fine, sharp, 
